Not an example, but there are many cases of people "working around" a patent. In this case, it is a spur to technological progress. That is, preventing progress

Not an example, but there are many cases of people "working around" a patent. In this case, it is a spur to technological progress. That is, preventing progress can encourage progress. There's a "prospect" theory for patenting (which with this student is probably familiar), that a patent is like staking a claim to minerals, with a samilar effect: that it encourages others to stake claims nearby, and so explore that region. If others could use the same area as the patent, they wouldn't be encouraged to explore, and you'd get a technological monoculture (in another sense, this would be greater progress, in that it is more widely adopted). I've been trying to think of an example, but I can't. I think the main way a patent can block progress is if the technology is not exploited well by the owner (like smalltalk being too expensive), and in such cases, we don't hear of it. When a patented technology is exploited successfully, money and time is reinvested in developing it, so that progress on it is accelerated.